To: Chuck Lever <chucklever@gmail.com>
Subject: Re: [PATCH] rpc.nfsd: add no-ipv4 and no-ipv6 options
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Date: Mon, 08 Jun 2015 10:33:22 -0400
From: Sean Elble <elbles@sessys.com>
Cc: Kinglong Mee <kinglongmee@gmail.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        linux-nfs-owner@vger.kernel.org
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On 08.06.2015 10:27, Chuck Lever wrote:
>> I don’t understand the need to “turn off” an address family. 
>> That’s what
>> /etc/netconfig is supposed to be for. What’s not happening here that
>> should be?
> 
> What I mean is: I’d rather not add more command line options if there
> is a way for rpc.nfsd to automatically and quietly do what is needed.
> But I don’t understand the use case here. Sean, can you explain it 
> for
> bears of little brain?

Sure, and please correct me if any of my understanding is incorrect (as 
it may well be).  In my environment, I wanted to have NFS only listen on 
one interface of a multihomed host.  In using the "--host" parameter to 
do so, I saw the error message regarding IPv6 thrown.  While disabling 
IPv6 globally in /etc/netconfig is an option (one I understand to be 
"global", in that it'd affect *all* applications on the host), it'd be 
nice to disable IPv6 for a single service/daemon instead.

Of course, the fact that at least Ubuntu and RHEL (and almost certainly 
their upstream and their derivatives, respectively) relay the error 
message when running the NFS init scripts could confuse someone into 
thinking NFS failed to start properly (until they look at the output of 
netstat -nalp, etc.).  I'd almost argue that's a larger concern. By the 
same token, "--host" seems a little used option, for whatever reason.

In any case, I'm the little brained one in this group.  :-)

-Sean